Non-impact printhead using a mask with a dye sensitive to and adjusted by light in a first spectrum to balance the transmission of light in a second spectrum emitted by an LED array
US4980701A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 3, 1989 |
| Grant date | Dec 25, 1990 |
| Priority date | — |
| Expiry date | Jul 3, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K15/1247
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An LED printhead includes an optical mask overlying the LED's to balance light outputs therefrom. The transmission density of the mask is adjusted for each LED in accordance with its respective light output to adjust same so that the light outputs from all LED's are the same. The mask comprises a UV fadeable dye whose transmission density is adjusted with a UV laser or other light source while monitoring the light output from the respective LED. The transmission density of the mask may be adjusted by a UV light source provided on the printhead during periods of nonuse of the printhead or the printhead may be removed from the recording apparatus for adjustment.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.